SLVAF52B July   2021  – November 2021 AFE8092 , TPS62913

 

  1.   Trademarks
  2. 1Introduction
  3. 2System Description
    1. 2.1 AFE80xx Noise and Ripple Requirements
    2. 2.2 AFE80xx Supply Settling and EVM for TDD Operations
    3. 2.3 Block Diagram
      1. 2.3.1 Proposed Power Architecture
      2. 2.3.2 Power Sequencing
    4. 2.4 Power Supply Design Consideration
  4. 3Tests and Results
    1. 3.1 Test Methodology
      1. 3.1.1 Phase Noise (Transmit) (dBc/Hz)
      2. 3.1.2 EVM for Frequency Division Multiplexing (FDD) Mode(%)
      3. 3.1.3 EVM for TDD Mode(%)
      4. 3.1.4 Receive (RX) Spectrum (Power Supply Spurious)
      5. 3.1.5 Power Efficiency
    2. 3.2 Test Conditions
    3. 3.3 Test Results
      1. 3.3.1 Phase Noise
      2. 3.3.2 EVM for FDD Mode
      3. 3.3.3 EVM for TDD Mode
      4. 3.3.4 RX Spectrum
      5. 3.3.5 Power Efficiency
  5. 4Conclusion
  6. 5References
  7. 6Revision History

2.3.2 Power Sequencing

In the proposed solution, sequencing is achieved by gating Power Good to Enable pin of DC-DC solution. For this application note for AFE8092 family, the sequencing is implemented using logic gates as shown in Figure 2-11 to meet the timing requirements on power rails as per AFE80xx specification in data sheet. R-C circuit on buffer output can be adjusted for fixed delay time across enable pulses to suppress any power good oscillations and additional soft start for DC-DC.

Figure 2-11 DC-DC Sequencing Circuit